Guide wire

ABSTRACT

The guide wire is a guide wire includes a distal portion and a main body portion. This guide wire is provided with a first curve portion; a second curve portion included on the distal side of aforesaid first curve portion and curved to the opposite direction with respect to aforesaid first curve portion; a third curve portion included on the distal side of aforesaid second curve portion and curved to the opposite direction with respect to aforesaid second curve portion, wherein a line contacting with both aforesaid first curve portion and aforesaid third curve portion has an obtuse angle with respect to an axis line of aforesaid main body portion.

TECHNICAL FIELD

This application is a continuation of International Application No.PCT/JP2007/054266 filed on Mar. 6, 2007, the entire content of which isincorporated herein by reference. This application also claims priorityunder 35 U.S.C. §119 based on Japanese Application No. 2006-059902 filedon Mar. 6, 2006 and Japanese Application No. 2006-125809 filed on Apr.28, 2006.

TECHNOLOGICAL FIELD

The present invention generally relates to a medical implement. Morespecifically, the invention pertains to a guide wire for introducing andaiming a medical device such as a catheter, an introducer kit or thelike used during medical treatment or diagnosis to a desired region in ablood vessel.

BACKGROUND DISCUSSION

A guide wire is used to introduce and indwell a medical device such as acatheter, an introducer kit or the like in a blood vessel when executingdiagnosis and medical treatment of the blood vessel percutaneously. Itwas common in the past that the region at which a medical device such asa catheter or the like was introduced into a blood vessel was thefemoral (FEMORAL). In recent years though, the introduction region isshifting to a brachial (BRACHIAL) and, in particular, to a radial(RADIAL) in order to lighten the burden on the patient. There has thusbeen a desire for a guide wire, including for example a guide wire witha J-shape distal tip, which possesses quite good steerabilitycharacteristics while also being capable of being used safely in a bloodvessel of an arm portion that often includes branches and meanders.

In the past, when a guide wire with a J-shape distal tip was insertedinto an introducing needle, a catheter or the like, a supplemental tool(inserter) has been used for making the insertion easier. However, in acase, in particular, in which the curvature radius of the curved portionof the J-shape is relatively small, the operation for inserting a guidewire once again into the inserter when exchanging the catheter or thelike was complicated.

To address this, there is disclosed a tool in which the need for asupplemental tool when inserting a wire into an introducing needle, acatheter, a sheath or the like is unnecessary. This is accomplished bydesigning the angle formed by the extended line in the direction of thedistal tip linear portion and the wire base line to be 40 to 700 withrespect to the distal shape of the guide wire. An example of this isdescribed in Patent Document 1 identified below.

Patent Document 2 identified below discloses a guide wire having adistal shape preformed as a multi-bending shape for use in entering aside opening of a tube for medical treatment. Also, Patent document 3identified below discloses a guide wire which includes two curveportions facing different directions in order to control the directionof the distal tip of the guide wire.

In case of a guide wire whose distal tip is formed to possess a J-shapeas seen in Patent Document 1, it is necessary to stretch the J-shapeddistal portion once and thereafter insert it into an introducing needle,catheter or a sheath. It thus often happens that the steerability of theguide wire is not very good.

Also, with respect to the guide wire disclosed in Patent Document 2, theinner diameter of the tube for medical treatment to be used is knownbeforehand, so that in when using a guide wire having a shapecorresponding to the inner diameter thereof, it is difficult for theguide wire to come out from the side opening of the tube for medicaltreatment. However, the blood vessel possesses a different diameterdepending on the individual organism, region or the like, so that incase of using the guide wire of Patent Document 2 for a blood vessel, itis necessary to separately use a guide wire which has a different shapefor every patient or for every region so as not to erroneously-enterinto a side-branch of a blood vessel. The guide wire disclosed in PatentDocument 3 is not as likely to erroneously-enter into a side-branch inthe case of a blood vessel having a thin side-branch. But in the case ofa blood vessel having a thick side-branch, it happens that the guidewire may erroneously-enter into the side-branch and it becomes difficultto reach the aimed region and therefore, the steerability is bad.

With respect to the guide wire described in Patent Document 4, the shapeof the guide wire is formed to be such a shape that it is possible toselect branches of both the vascular channels having large and smalldiameters. However, it is relatively easy to erroneously-enter into abranch for that reason and it happens that it will spend time for theoperation after all in case of introducing it from the radial asmentioned above.

Further, Patent Document 5 identified below discloses a guide wirehaving an S-shape distal shape to introduce it into a blood vesselbranch. But a guide wire such as that having an S-shape distal tip facesthe hand direction at the most distal tip thereof, so that it isdifficult to insert it into an introducing needle or a catheter, and soit is necessary to also use an inserter.

[Patent Document 1] Japanese Unexamined Patent Publication No.2004-181184.

[Patent Document 2] Japanese Unexamined Patent Publication No.H11-76415.

[Patent Document 3] Japanese Unexamined Patent Publication No.2003-530132.

[Patent Document 4] Japanese Unexamined Patent Publication No.2003-508168.

[Patent Document 5] Japanese Utility Model Patent Publication No.S61-7736.

SUMMARY

According to one aspect, a guide wire comprises an elongated membercomprised of a straight main body portion and a curved distal portionpositioned on a distal side of the straight main body portion, whereinthe curved distal portion of the elongated member comprises a firstcurve portion, a second curve portion and a third curve portion. Thefirst curve portion is more flexible than the main body portion, and thefirst curve portion immediately follows the distal end of the straightmain body portion. The second curve portion is positioned distally ofthe first curve portion, and the second curve portion curves in adirection of curvature that is opposite the direction of curvature ofthe first curve portion. The second curve portion is more flexible thanthe first curve portion, and the third curve portion is positioneddistally of the second curve portion. The third curve portion curves ina direction opposite the direction of curvature of the second curveportion. A line contacting both the first curve portion and the thirdcurve portion forms an obtuse angle with respect to the axis of the mainbody portion.

In accordance with another aspect, a guide wire comprises an elongatedmember comprised of a main body portion and a distal portion positionedon a distal side of the main body portion, wherein the elongated membercomprises a first curve portion curving in a direction of curvature, asecond curve portion and a third curve portion. The second curve portionis positioned on the distal side of the first curve portion and curvesin a direction of curvature that is opposite the direction of curvatureof the first curve portion. The third curve portion is positioned on thedistal side of the second curve portion and curves in a directionopposite the direction of curvature of the second curve portion. A linecontacting both the first curve portion and the third curve portionforms an obtuse angle with respect to the axis of the main body portion.

This construction of the guide wire results in a guide wire whosesteerability is quite good when operating the guide wire. In particular,as a guide wire which is to be introduced from a radial artery of awrist, it is difficult to erroneously-enter into side-branches withrespect to inter-individual differences and various blood vesseldiameters reaching until the left ventricle and it is possible to insertit relatively smoothly to the aimed region.

It is preferable for the most distal tip of the guide wire to bepositioned between the line contacting the first and second curveportions and a line which is parallel with such line and contacts thesecond curve portion.

Thus, when inserting a guide wire into a tubular medical device such as,for example, an introducing needle, a catheter, a sheath or the like, itis possible to execute the insertion operation relatively easily andreliably.

The direction of the portion of the guide wire shifting from the firstcurve portion to the second curve portion preferably forms a largerangle with respect to the axis line of the main body portion comparedwith the angle formed by the direction in which the most distal tip isdirected with respect to the axis line of the main body portion.

With this construction, when inserting a guide wire into a tubularmedical device such as, for example, an introducing needle, a catheter,a sheath or the like, it is possible to execute the insertion operationquite easily and also with relative certainly.

The portion of the guide wire shifting from the second curve portion tothe third curve portion can be parallel to the axis line of the mainbody portion.

Thus, when inserting a guide wire into a tubular medical device such as,for example, an introducing needle, a catheter, a sheath or the like, itis possible to relatively easily and reliably execute the insertionoperation.

It is also possible to configure the guide wire so that the portion ofthe guide wire shifting from the second curve portion to the third curveportion to be oriented in a direction diverging from or convergingtowards the axis line of the main body portion in the distal direction.

This configuration can also help facilitate the insertion operation ofinserting the guide wire into a tubular medical device such as, forexample, an introducing needle, a catheter, a sheath or the like.

The guide wire disclosed here includes a distal portion and a main bodyportion, with the distal portion being provided with a curve portion.The steerability of the guide wire is thus quite good when operating theguide wire.

The first curve portion is preferably more flexible (has a higherflexibility) than the main body portion, and the second curve portion ispreferably more flexible (has a higher flexibility) than the first curveportion.

When inserting a guide wire into a curved blood vessel, it is thuspossible for the distal portion of the guide wire to follow the shape ofthe blood vessel. Consequently, the steerability when operating theguide wire is improved. Even if the most distal tip of the guide wiregets into a branch, it turns around, advances in the main blood vesseland does not erroneously-enter into a branch.

According to another aspect, a guide wire comprises an elongated membercomprised of a main body portion and a distal portion positioned on adistal side of the main body portion, a first curve portion provided atthe distal portion of the elongated member, with the first curve portioncurving in a direction of curvature, a second curve portion positioneddistally of the first curve portion and curving in a direction ofcurvature that is opposite the direction of curvature of the first curveportion, and a third curve portion positioned distally of the secondcurve portion and curved in a direction opposite the direction ofcurvature of the second curve portion. The first curve portion possessesa higher flexibility than the main body portion, and the second curveportion possesses a higher flexibility than the first curve portion.

The guide wire is thus constructed in a way such that the steerabilityof the guide wire is relatively excellent when operating the guide wire.Even if the most distal tip of the guide wire gets into a branch, itturns around, advances in the main blood vessel and does noterroneously-enter into a branch.

It is preferable for the third curve portion to have a higherflexibility, or the same flexibility, compared with the second curveportion.

With this construction, when inserting the guide wire into a curvedblood vessel, it is possible for the distal portion of the guide wire tofollow the shape of the blood vessel. Consequently, the steerabilitywhen operating a guide wire is improved.

The guide wire is preferably composed of a core wire including a distalportion and a coating portion which covers at least the distal portionof the core wire and which is constituted by a resin. This helps improvethe steerability of the guide wire when operating the guide wire.

The distal portion of the core wire of the guide wire preferablyincludes a flat portion. Thus, higher flexibility is exhibited at theflat portion.

It is preferable for the core wire at which the third curve portion ispositioned to be a flat portion and for the third curve portion to havea higher flexibility compared with the second curve portion. Thus, muchhigher flexibility is exhibited at the flat portion and consequently,the steerability of the guide wire is improved when operating the guidewire.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

FIG. 1 is a partially enlarged side view showing one embodiment of aguide wire disclosed here.

FIGS. 2A-2D are schematic illustrations of other embodiments of a guidewire disclosed here.

FIG. 3 is a perspective view showing the internal structure of a guidewire disclosed here.

FIG. 4 is a perspective enlarged view showing a portion of the internalstructure of the guide wire depicted in FIG. 3.

FIG. 5 is a partially enlarged view of another embodiment of a guidewire disclosed here.

FIGS. 6A-6F are cross-sectional views of portions of the guide wiretaken along the correspondingly lettered section lines shown in FIG. 5.

FIGS. 7A-7F are cross-sectional views of portions of another embodimentof a guide wire taken along section lines corresponding in position tothe correspondingly lettered section lines in FIG. 5.

FIGS. 8A-8F are cross-sectional views of portions of another embodimentof a guide wire taken along section lines corresponding in position tothe correspondingly lettered section lines in FIG. 5.

FIGS. 9A-9F are cross-sectional views of portions of another embodimentof a guide wire taken along section lines corresponding in position tothe correspondingly lettered section lines in FIG. 5.

FIG. 10 is a cross-sectional view of a guide wire according to anotherembodiment disclosed here.

FIG. 11 is a plan view of a specific configuration of the guide wireshown in FIG. 1.

FIG. 12 is a plan view of a specific configuration of comparativeexample 1 of a guide wire used for testing and evaluation.

FIG. 13 is a plan view of a specific configuration of comparativeexample 2 of a guide wire used for testing and evaluation.

FIG. 14 is a plan view of a specific configuration of comparativeexample 3 of a guide wire used for testing and evaluation.

FIG. 15 is a plan view of a specific configuration of comparativeexample 4 of a guide wire used for testing and evaluation.

FIG. 16 is a plan view of a specific configuration of comparativeexample 5 of a guide wire used for testing and evaluation.

FIG. 17 is a schematic illustration of an evaluation tool used to testand evaluate the guide wires shown in FIGS. 11-16.

FIG. 18 is a schematic illustration of another evaluation tool used totest and evaluate the guide wires shown in FIGS. 11-16.

DETAILED DESCRIPTION

A guide wire according to one embodiment disclosed here is illustratedin FIG. 1. The guide wire 1A according to this embodiment is a guidewire comprised of an elongated member composed of a distal portion 10and a main body portion 20. The elongated member, specifically thedistal portion 10 of the guide wire, includes multiple curve portions.More specifically, the distal portion 10 includes a first curve portion31 subsequent to or immediately following the distal side of the mainbody portion 20 and a second curve portion 32 positioned on the distalside of the first curve portion 31 and curved in a direction oppositethe direction of curvature of the first curve portion 31. It is alsopossible to include a linear (i.e., non-curved) portion between thefirst curve portion 31 and the second curve portion 32 so that the twocurved portions 31, 32 are separated by a portion which is not curved.In the illustrated embodiment, the main body portion 20 is straight orlinear, with the distal end of the straight main body portion directlymerging into the first curve portion.

The distal portion 10 of the guide wire further comprises a third curveportion 33 positioned on the distal side of the second curve portion 32and curved in a direction opposite the direction of curvature of thesecond curve portion 32. Once again, it is also possible to include alinear (i.e., non-curved) portion between the second curve portion 31and the third curve portion 32 so that the two curved portions 32, 33are separated by a portion which is not curved. The distal side of thethird curve portion 33 is terminated by the most distal tip 12. Thefirst curve portion 31, the second curve portion 32 and the third curveportion 33 are constituted in the same plane.

The guide wire 1A is configured so that a line A contacting both thefirst curve portion 31 and the third curve portion 32 forms an obtuseangle with respect to the central axis (line Y) of the main body portion20 in the guide wire's natural state (an obtuse angle extending from theline A to the axis (line) Y of the main body portion 20 in the clockwisedirection). Here, “natural state” means a state in which an externalforce is not applied to the guide wire 1A. The axis (axis line) Y refersto the central axis of the portion (linear or straight portion) of theguide wire proximally adjoining the first curve portion 31. It ispreferable for the angle K between the line A and the axis line Y to be20 to 45 degrees, more preferably 25 to 42 degrees. The line Areferenced above is a line A passing through a contact point 51 of thefirst curve portion 31 and a contact point 53 of the third curve portion33. The contact point 51 represents the vertex of the first curveportion 31 while the contact point 53 represents the vertex of thesecond curve portion 33. The contact points 51, 53 are also theoutwardmost point in the direction of curvature of the first and thirdcurve portions 31, 33 respectively.

The most distal tip 12 of the guide wire 1A is positioned between theline A, which contacts both the first curve portion 31 and the thirdcurve portion 32, and a line B which is parallel with the line A andcontacts the second curve portion 32. The line B passes through acontact point 52 of the second curve portion 32. The contact point 52 isthe vertex of the second curve portion 32. Also, the contact point 52represents the outwardmost point in the direction of curvature of thesecond curve portion 32.

The direction M of the guide wire portion 71 shifting from the firstcurve portion 31 to the second curve portion 32 (where the direction Mis indicated by the central axis of the guide wire portion 71 shiftingfrom the first curve portion 31 to the second curve portion 32) forms anangle with respect to the axis line Y larger than the angle which thedirection N of the distal-most tip 12 forms with the axis line Y (wherethe direction N refers to the central axis of the distal-most tip 12).Thus, the axial centerline M of a portion of the guide wire between thefirst and second curved portions 31, 32 forms an angle with the axisline Y that is larger than the corresponding angle between the axialcenterline N of the distal most portion of the guide wire and the axisline Y. The direction L of a portion 72 of the guide wire shifting fromthe second curve portion 32 to the third curve portion 33 (where thedirection L is indicated by the central axis of the guide wire portion72 shifting from the second curve portion 32 to the third curve portion33) is a direction diverging away from the axis line Y in the distaldirection. That is, the portion 72 is oriented so that the line Ldiverges from the axis line Y towards the distal direction (i.e., towardthe top of the page in FIG. 1).

It is preferable for the distance D between the line A and the line B tobe 2 to 11 mm, more preferably 4 to 9 mm. If the distance D is too small(e.g., smaller than 2 mm), the most distal tip 12 may contact the bloodvessel wall when advancing in the blood vessel and there is a higherlikelihood for the erroneous-entering, for example to side branches. Ifthe distance D is excessively large (e.g., larger than 11 mm), thedistal most tip 12 may contact the blood vessel wall in case ofadvancing in a comparatively thin blood vessel. It is preferable for thedistance E between a vertex 52 of the second curve portion 32 and theaxis line Y of the main body portion 20 to be 9 to 16 mm, morepreferably 10 to 15 mm. If the distance E is excessively small (e.g.,smaller than 9 mm), the second curve portion 32 does not contact theblood vessel wall when advancing in a rather thick blood vessel and themost distal tip 12 will approach or contact the blood vessel wall, inwhich more chances occur for the erroneous-entering to side-branches. Ifthe distance E is excessively large (e.g., larger than 16 mm), thesecond curve portion 32 tends to exhibit a state of spreading whenadvancing in a rather thin blood vessel and the most distal tip 12 isreflexed, in which more chances occur for contact with the blood vesselwall and the possibility of the erroneous-entering becomes high.

The guide wire 1A includes a core wire and a coating portion whichcovers at least the distal portion of the core wire and which isconstituted by a resin. It is preferable for the core wire to be an NiTialloy wire. It is preferable for the resin of the coating portion to bepolyurethane. It is preferable for the front face of the coating portionto be coated with a hydrophilic polymer. The distal portion 10 of thecore wire possesses a tapered shape so that the distal portion 10 ismore flexible than the main body portion 20.

It is relatively easy for the guide wire 1A to be inserted into anintroducing needle, a catheter or a sheath. Specifically, it is possibleto relatively easily insert the guide wire 1A into a catheter includinga catheter main body of tubular shape having elasticity and a hubinstalled at the proximal portion of the catheter main body and into theaforesaid hub from the distal side thereof.

Also, the guide wire 1A is not as susceptible to erroneously enteringinto a side-branch in a blood vessel and it can reach an aimed regionquite speedily. Specifically, when inserting the guide wire 1A into ablood vessel and in a case in which the blood vessel thereof is in astraight line shape, the most distal tip 12 of the guide wire 1A isinhibited or prevented from touching the blood vessel wall. Also, in acase in which there exists, at a position of a blood vessel into whichthe guide wire 1A is inserted, a side-branch (blood vessel) branchingfrom the blood vessel thereof, the distal portion 10 of the guide wire1A is prevented from entering into the side-branch unwillingly. Thus, itis possible for the guide wire 1A to reach an aimed region in a bloodvessel speedily.

FIG. 2A schematically illustrates the guide wire shown in FIG. 1. FIGS.2B-2D schematically illustrate other embodiments 1B, 1C, 1D of the guidewire.

With respect to the guide wire 1B, the direction L of the portionshifting from the second curve portion to the third curve portion isparallel (inclusive of approximately parallel to) the axis line Y. Inthe guide wire 1C, the direction L of the portion shifting from thesecond curve portion to the third curve portion is such that thedistance between the line L and the axis line Y narrows toward thedistal tip (i.e., the line Y approaches the axial line Y in the distaldirection). In the guide wire 1D, similar to the guide wire 1A, thedirection L of the portion shifting from the second curve portion to thethird curve portion is such that the distance between the line L and theaxis line Y increases toward the distal tip (i.e., the line Y divergesaway from the axial line Y in the distal direction). The embodimentshown in FIG. 2D differs from the embodiment of the guide wireillustrated in FIG. 1 (FIG. 2A) in that the FIG. 2D embodiment of theguide wire is constructed such that the divergence between the line Land the axial line Y is greater towards the distal direction than in theembodiment shown in FIG. 1 (FIG. 2A).

FIG. 3 is a perspective view showing the internal structure of a guidewire disclosed here. To facilitate an understanding and illustration ofthe internal structure, the curve portions of the distal portion 10 areomitted in FIG. 3. The guide wire 1E shown in FIG. 3 includes a corewire 40 comprised of a core wire distal portion 41 and a coating portion60 covering at least the core wire distal portion 41. The coatingportion 60 is preferably composed of a resin. The core wire 40 comprisesseveral portions. In the illustrated embodiment, the core wire 40comprises a core wire main body portion 42, a taper portion 44 and thecore wire distal portion 41. The material forming the core wire 40 canbe NiTi alloy or stainless steel. It is preferable for the core wire 40to be composed of a superelastic alloy. The core wire main body portion42 possesses a circular cross-sectional shape. The taper portion 44 isprovided at the distal side of the core wire main body portion 42. Thetaper portion 44 is constructed such that its outer diameter becomesgradually smaller toward the distal tip. In the illustrated embodiment,the taper portion 44 tapers in outer diameter at a constant rate, thoughit is also possible to employ a configuration in which the taper anglechanges at a portion of the taper portion. For example, a configurationcan be employed in which the taper angle on the proximal side is largerthan the taper angle on the distal side. Also, it is possible to employa structure in which the taper angle on the proximal side is smallerthan the taper angle on the distal side.

The core wire distal portion 41 is provided on the distal side of thetaper portion 44. The core wire distal portion 41 includes a flatportion 46. The flat portion 46 has a width and thickness, with thewidth being larger than the thickness. With the illustratedconfiguration, the flat portion 46 can be bent in the thicknessdirection more easily. It is also possible for the core wire distalportion 41 to include an outer diameter uniform portion (a portion ofuniform or constant outer diameter) on the distal side of the taperportion 44. In this case, a transition portion can be located on thedistal side of the outer diameter uniform portion, with the flat portion46 following. The transition portion provides a transitions from theouter diameter uniform portion to the flat portion. The cross-sectionalarea of the core wire main body portion 42 is larger than thecross-sectional area of the core wire distal portion 41. It ispreferable for the flat portion 46 to be superelastic. In aload-distortion curve, the elastic modulus in the elastic region of theflat portion 46 is preferably smaller than the elastic modulus in theelastic region of the core wire main body portion 42. Based on such aconstruction, it is possible to impart flexibility even if the thicknessof the flat portion 46 is not extremely small.

The coating portion 60 covering the core wire distal portion 41 iscomposed of a resin such as polyurethane or the like. In this disclosedembodiment, the coating portion 60 covers the core wire distal portion41, the core wire main body portion 42 and the taper portion 44.However, it is also possible to utilize the cover portion 60 so that itcovers only the core wire distal portion 41. In addition, it is alsopossible for the coating portion 60 to cover only the core wire distalportion 41 and the taper portion 44.

The flat portion 46 of the core wire distal portion 41 can also beprovided with an elastic portion. Referring to FIG. 4, one way ofaccomplishing this is to provide an elastic portion 48 thinner than theflat portion 46 at an intermediate part of the flat portion 46. Thewidth of the elastic portion 48 is preferably wider (greater) than thewidth of the flat portion 46. To help maintain the strength of theelastic portion 48, it is preferable to employ a structure in which thecross-sectional area of the flat portion 46 and the cross-sectional areaof the elastic portion 48 are equal (inclusive of approximately equal).It is also possible to employ a structure in which the width of theelastic portion 48 is the same as the width of the flat portion 46 bymaking the thickness of the elastic portion 48 thinner than thethickness of the flat portion 46. For another example of the elasticportion, it is possible to provide the elastic portion by changing thematerial property using thermal treatment or the like. As mentioned, thecurve portions of the distal portion 10 of the guide wire 1E are notspecifically illustrated in FIG. 3 to help facilitate the illustrationof the internal structure. However, it is to be understood that theguide wire includes curve portions as discussed above, and the guidewire 1E can possess any of the shapes associated with the guide wires1A, 1B, 1C and 1D.

FIG. 5 illustrates, in a partially enlarged manner, another embodimentof a guide wire disclosed here. The guide wire 1F can be provided withthe structure shown in FIG. 3 and the shape of the guide wire 1A iscomprised of the distal portion 10 and the main body portion 20. Thedistal portion 10 is provided with the first curve portion 31, thesecond curve portion 32 and the third curve portion 33. The second curveportion 32 is positioned on the distal side of the first curve portion31, and is curved in a direction opposite the direction of curvature ofthe first curve portion 31. The third curve portion 33 is positioned onthe distal side of the second curve portion 32 and is curved in adirection opposite the direction of curvature of the second curveportion 32. The first curve portion 31 has a higher (greater)flexibility compared with the main body portion 20. The second curveportion 32 has a higher (greater) flexibility compared with the firstcurve portion 31. The third curve portion 33 has the same flexibilitycompared with the second curve portion 32, though it is also possiblefor the third curve portion 33 to have a higher (greater) flexibilitythan the second curve portion 32.

FIGS. 6A-6F illustrate cross-sectional views (perpendicular to the axisof the guide wire 1E) of the guide wire shown in FIG. 5 taken along thecorrespondingly lettered section lines noted in FIG. 5.

FIG. 6A shows the cross-sectional view of the main body portion 20 ofthe guide wire 1E. As illustrated, the guide wire 1E is composed of thecore wire main body portion 42 of the core wire 40 and the coatingportion 60 covering the periphery of the main body portion 42 in aconcentric manner. The core wire main body portion 42 and the coatingportion both possess circular cross-sectional shapes.

FIG. 6B illustrates a cross-section through the section line B-B in FIG.5 and represents the cross-section of a portion of the guide wirepositioned on the proximal side of the first curve portion 31 and on theaxis line of linear portion of the main body portion 20. The position ofthe cross-section B-B is taken at the taper portion 44 in the core wire40. The cross-sectional area of the taper portion 44 of the core wire 40is smaller than the cross-sectional area of the core wire main bodyportion 42 in FIG. 6A.

FIG. 6C illustrates a cross-section through the section line C-C in FIG.5 and represents the cross-section at the vertex of the first curveportion 31 (point 51 in FIG. 1). The position of the FIG. 6Ccross-section is at the taper portion 44 in the core wire 40, at aposition on the distal side of the taper portion 44 relative to thecross-section B-B. The cross-sectional area of the taper portion 44 ofthe core wire 40 in the cross-sectional view of FIG. 6C-6C is smallerthan the cross-section area of the taper portion 44 shown in FIG. 6B.The vertex of the first curve portion 31 is positioned between the startportion (proximal-most point) and the end portion (distal-most point) ofthe taper portion 44 of the core wire 40. The end portion of the taperportion 44 is positioned on the distal side of the vertex of the firstcurve portion 31. The first curve portion 31 is positioned at the taperportion 44 of the core wire 40 so that the first curve portion 31 andthe taper portion 44 overlap one another or are coextensive with oneanother for at least a portion of their longitudinal extent. The corewire 40 in the first curve portion 31 is in the taper portion 44, sothat the first curve portion 31 has a higher flexibility than the mainbody portion 20.

FIG. 6D illustrates a cross-section through the section line D-D in FIG.5 and represents the cross-section of the guide wire at the vertex(point 52 in FIG. 1) of the second curve portion 32. The position of thecross-section shown in FIG. 6D is in the flat portion 46 in the corewire 40. The core wire 40 in the second curve portion 32 is in the flatportion 46, and so the second curve portion 32 has a higher flexibilitythan the first curve portion 31. The cross-sectional area of the flatportion 46 in the second curve portion 32 is smaller than thecross-sectional area of the taper portion 44 in the first curve portion31. The thickness of the flat portion 46 is smaller than the outerdiameter of the taper portion 44 in the first curve portion 31.Therefore, the second curve portion 32 has a higher flexibility than thefirst curve portion 31. With this construction, the guide wire is not aslikely to erroneously enter into a side-branch even if the most distaltip 12 of the guide wire 1E gets into a side-branch caused by a factthat the flexible second curve portion 32 is bent more before the mostdistal tip 12 is further inserted and the guide wire advances in themain blood vessel with the second curve portion 32 being set at theforefront.

FIG. 6E illustrates a cross-section through the section line E-E in FIG.5 and represents the cross-section of the guide wire at the vertex(point 53 in FIG. 1) of the third curve portion 33. The position of thecross-section shown in FIG. 6E is at the flat portion 46 in the corewire 40. The core wire 40 at the third curve portion 33 is in the sameflat portion 46 as the second curve portion 32, so that the flexibilityof the third curve portion 33 is the same as the flexibility of thesecond curve portion 32.

FIG. 6F illustrates a cross-section of the guide wire through thesection line F-F in FIG. 5 and represents the cross-section of the guidewire at the most distal tip 12. The position of the section line F-F isat the flat portion 46 in the core wire 40. The core wire 40 at the mostdistal tip 12 is in the same flat portion 46 as the second curve portion32 and the third curve portion 33, and so the flexibility of the thirdcurve portion 33 is the same as the flexibility of the second curveportion 32 and the third curve portion 33.

FIGS. 7A-7F illustrate cross-sectional views (perpendicular to the axisof the guide wire) of another embodiment of the guide wire, taken atpositions corresponding to the correspondingly lettered section linesnoted in FIG. 5.

FIGS. 7A-7F show another embodiment of the guide wire in which thecross-sectional views shown in FIGS. 7A, 7D, 7E and 7F are the same asthose shown in FIGS. 6A, 6D, 6E and 6F, respectively, but thecross-sectional area of the core wire 40 in FIG. 7B (corresponding tothe position of the section line B-B in FIG. 5) is smaller than thecross-sectional area of the core wire 40 in the FIG. 6B cross-section,and the core wire 40 in FIG. 7C (corresponding to the position of thesection line C-C in FIG. 5) is positioned at the flat portion 46. Thecross-sectional area of the flat portion 46 shown in the FIG. 7Ccross-section is smaller than the cross-sectional area of the taperportion 44 in the FIG. 7B cross-section. The core wire 40 in the firstcurve portion 31 is in the flat portion 46, and so the first curveportion 31 has higher flexibility (i.e., is more flexible) than the mainbody portion 20.

FIGS. 8A-8F show another embodiment of the guide wire in which thecross-sectional views of the guide wire shown in FIGS. 8A, 8B. 8C, 8Dand 8F are the same as those shown in FIGS. 6A, 6B, 6C, 6D and 6F,respectively, but the cross-sectional view shown in FIG. 8E differs withrespect to the elastic portion 48 of the core wire 40. As shown in FIG.8E, the elastic portion 48 is thinner than the flat portion 46. Thewidth of the elastic portion 48 is also wider than the width of the flatportion 46. Consequently, the third curve portion 33 has a higherflexibility than the second curve portion 32.

FIGS. 9A-9F illustrate another embodiment of the guide wire in which thecross-sectional views of the guide wire shown in FIGS. 9A and 9B are thesame as those shown in FIGS. 6A and 6B, respectively. Thecross-sectional area of the taper portion 44 shown in FIG. 9C (taken ata position on the guide wire corresponding to the section line C-C inFIG. 5) is larger than the cross-sectional area of the taper portion 44shown in FIG. 6C. Also, the cross-sectional area of the taper portion 44shown in FIG. 9D (taken at a position on the guide wire corresponding tothe section line D-D in FIG. 5) is smaller than the cross-sectional areaof the taper portion 44 shown in FIG. 6D. With this construction, thesecond curve portion 32 has a higher flexibility than the first curveportion 31. The core wire 40 in FIG. 9E and FIG. 9F is in the flatportion 46 of the core wire. The thicknesses of the flat portions 46 inthese sections shown in FIGS. 9E and 9F represent are the same and aresmaller than the thickness of the flat portion 46 in FIG. 6E and FIG.6F. By virtue of this construction, the third curve portion 33 possessesa higher flexibility than the first curve portion 31 and the secondcurve portion 32. Thus, even if the most distal tip 12 of the guide wiremoves into a branch, it turns around at the third curve portion 33 andadvances in the main blood vessel, and so erroneous-entering into abranch is inhibited or prevented.

FIG. 10 is a cross-sectional view of another embodiment of a guide wiredisclosed here.

FIG. 10 shows an embodiment of the guide wire for softening (making moreflexible) the curve portion. As shown in FIG. 10, the guide wire isprovided with a groove 80 in a direction perpendicular (inclusive ofsubstantially perpendicular) to the axis on the surface (outer surface)of the coating portion 60 of at least the inner side of the curveportion. The groove 80 possess a spiral shape and is provided on theouter surface of the curve portion. For example, the groove 80 isprovided on the entire outer circumference of the surface of the coatingportion 60 of the second curve portion 32 and the third curve portion 33in FIG. 1, FIG. 2 or FIG. 5. The groove 80 is provided only on thesurface of the coating portion 60 of the curve portion. As shown in FIG.10, the horizontal cross-section of the groove 80 is such that thevertical cross-section shape of the outer surface (outer circumferenceface) of the coating portion 60 possesses a wave shape. It is possibleto obtain the wave shaped groove 80 by, for example, winding a wire 70on the coating portion 60 with a gap for the outer diameter of the wire70 and by heating it. More specifically, and by way of example, the wire70 may be wound with tension on the coating portion 60 which has asmooth and non-groove surface. The wire 70 may be wound such that eachturn (winding) of the wound wire 70 is spaced apart from the adjacentturn (winding) by a distance that is the same as the outer diameter ofthe wire 70 in order to ultimately make the wave shaped groove 80.Thereafter, the coating portion 60 with the wound wire 70 may be heatedto soften the coating portion. The wire 70 wound on the coating portion60 is able to dig into the softened coating portion 60 as shown in FIG.10. Finally the wire 70 may then be removed from the coating portion 60,with the result being the grooved surface.

It is also possible for the groove 80 to be in a loop shape other thanin a spiral shape. Also, it is possible to employ a slit shape insteadof a groove 80. The groove 80 can be provided only on the front face ofthe coating portion 60 on the inner side of the curve portion, forexample, the second curve portion 32 and the third curve portion 33 inFIG. 1, FIG. 2 or FIG. 5.

In the present embodiments, the flexibility of the curve portion isincreased by providing a groove 80 or a slit almost perpendicular to theaxial direction on the front face of the coating portion 60 at least onthe inner side of the curve portion, so that the curve portion can bemore easily bent.

Aforesaid illustrative embodiment for softening the curve portion can beused in connection with each of the embodiments of the guide wiredescribed above.

Softening the curve portion(s) of the guide wire to make the curveportion(s) more flexible can be also realized by thermally-treating thecore wire at the curve portion and by converting or transforming it to amaterial having a higher flexibility compared with other portions.

It is possible to use the guide wires disclosed here to introduce amedical device such as a catheter, a sheath or the like from a radial, abrachial and a femoral to an aimed region such as a chest region, anabdominal region or the like, and the use of the guide wires describedand illustrated here is not limited to being used in the noted contextssuch as where the guide wire-introduced region is a radial, brachial orfemoral where the guide wire might otherwise have a tendency to becomestuck during use.

The description which follows describes concrete examples of guide wiresproduced according to the disclosure herein.

1. Manufacturing of Guide Wire

Inventive Example

A guide wire shown in FIG. 11 was manufactured so that the guide wirehas an outer diameter of 0.89 mm and a full length of 1500 mm. The corewire composing the guide wire was made of Ni—Ti and the coating portionwas made of polyurethane. Also, with respect to the flat portion, thelength of the flat portion was 4 mm, the width of the flat portion 0.23mm and the thickness of the flat portion was 0.03 mm. Also, the guidewire was fabricated so that the distance D was about 8.5 mm and thedistance E was about 13.5 mm.

Comparative Example 1

A guide wire shown in FIG. 12 was manufactured. The outer diameter, thefull length and the constituent material of this guide wire were similarto those discussed above in the inventive example.

Comparative Example 2

A guide wire shown in FIG. 13 was manufactured. The outer diameter, thefull length and the constituent material of the guide wire were similarto those discussed above in the inventive example.

Comparative Example 3

A guide wire shown in FIG. 14 was manufactured. The outer diameter, thefull length and the constituent material of the guide wire were similarto those discussed above in the inventive example.

Comparative Example 4

A guide wire shown in FIG. 15 was manufactured. The outer diameter, thefull length and the constituent material of the guide wire were similarto those discussed above in the inventive example.

Comparative Example 5

A guide wire shown in FIG. 16 was manufactured. The outer diameter, thefull length and the constituent material of the guide wire were similarto those discussed above in the inventive example.

In FIG. 11 to FIG. 16, the units of length are always “mm”.

2. Evaluation

2.1 Evaluation Using the Evaluation Tool Shown in FIG. 17

With respect to the guide wires obtained by the inventive example andthe respective comparative examples, evaluations were executed using theevaluation tool shown in FIG. 17. The evaluation tube includes a “maintube” and a “side tube.” This evaluation tool is a tool based on theassumption of a straight-line shaped blood vessel and a side-branchbranching from the blood vessel at a point along the length of the bloodvessel. In the FIG. 17 illustration, the “main tube” corresponds to the“straight-line shaped blood vessel” and the “side tube” corresponds tothe “side-branch”. The main tube and the side tube are both made ofpolypropylene.

The evaluation was executed by preparing evaluation tools 1 a to 5 a inwhich the inner diameters φd1 of the main tubes and the inner diametersφd2 of the side tubes are respectively different (as noted in the tablebelow). The testing involved inserting the guide wire from the distalside thereof into the main tube of each evaluation tool five times.Evaluation was performed to determine whether or not the distal portionof the guide wire intrudes into the side tube at least once within thosefive times for each evaluation tool. The evaluation criteria were asfollows.

∘: means a case in which the distal portion of the guide wire did notintrude into the side tube at all (i.e., did not intrude into the sidetube of the respective evaluation tool in any of the five insertions).

x: means a case in which the distal portion of the guide wire intrudedinto the side tube at least once.

The evaluation results are shown in Table 1.

TABLE 1 Evaluation Evaluation Evaluation Evaluation Evaluation Tool 1aTool 2a Tool 3a Tool 4a Tool 5a φd1: φd1: φd1: φd1: φd1: 4 mm 4 mm 5 mm6 mm 8 mm φd2: φd2: φd2: φd2: φd2: Guide Wire 1 mm 2 mm 2 mm 3 mm 8 mmInventive ◯ ◯ ◯ ◯ ◯ Example 1 Comparative ◯ ◯ ◯ X X Example 1Comparative ◯ X ◯ ◯ ◯ Example 2 Comparative ◯ X X X ◯ Example 3Comparative ◯ X X X X Example 4 Comparative ◯ ◯ ◯ ◯ ◯ Example 52.2 Evaluation Using the Evaluation Tool Shown in FIG. 18

With respect to the guide wires obtained by the inventive example andthe respective comparative examples, evaluations were executed using theevaluation tool shown in FIG. 18. This evaluation tool is a tool basedon the assumption of a curved blood vessel (Ulnar Loop) and aside-branch branching from the central portion of the curve portion ofthe blood vessel toward the outside. In the FIG. 18 illustration of theevaluation tool, the “main tube” corresponds to the “curved bloodvessel” and “side tube” corresponds to the “side-branch”. The main tubeand the side tube are both made of polypropylene.

Here, testing and evaluation similar to that described above wereperformed by preparing five evaluation tools 1 b to 5 b in which theinner diameters φd1 of the main tubes and the inner diameters ×φd2 ofthe side tubes are respectively different as noted in the table below.

The evaluation results using evaluation tools 1 a-5 a are shown in Table2.

TABLE 2 Evaluation Evaluation Evaluation Evaluation Evaluation Tool 1aTool 2a Tool 3a Tool 4a Tool 5a φd1: φd1: φd1: φd1: φd1: 4 mm 4 mm 5 mm6 mm 8 mm φd2: φd2: φd2: φd2: φd2: 1 mm 2 mm 2 mm 3 mm 8 mm Guide WireR: 10 mm R: 10 mm R: 10 mm R: 10 mm R: 20 mm Inventive ◯ ◯ ◯ ◯ ◯ Example1 Comparative ◯ ◯ ◯ ◯ X Example 1 Comparative ◯ X ◯ ◯ X Example 2Comparative ◯ X X X X Example 3 Comparative ◯ ◯ ◯ ◯ X Example 4Comparative ◯ ◯ ◯ ◯ X Example 5

As clear from Table 1 and Table 2, with respect to the guide wireobtained by the inventive example, the distal portion of the guide wiredid not intrude into the side tube at all in any of the evaluationtools.

On the other hand, with respect to the guide wires obtained byrespective comparative examples, each of the guide wires experienced atleast one instance in which the distal portion of the guide wireintruded into the side tube.

Also, the guide wires shown in FIG. 2 and FIG. 5 to FIG. 10 weremanufactured, and testing and evaluations similar to those of theaforesaid inventive example were executed with respect to them. Similarresults as those of the aforesaid inventive example were obtained alsowith respect to the guide wires shown in FIGS. 2 and 5-10.

2.3 Evaluation by Using Catheter

With respect to the guide wires obtained by the inventive example andthe comparative examples, evaluations were also carried out using acatheter. This catheter was a catheter including a tube-shaped cathetermain body having elasticity and a hub installed at the proximal portionof the aforesaid catheter main body. The hub was a hub having acylindrical shape and communicates with the catheter main body. Also,the inner diameter of the catheter main body was φ1.05 mm and the innerdiameter of the hub entrance port was φ4 mm.

Here, insertion of the guide wire from the distal side thereof withrespect to the hub was attempted five times and an evaluation wasconducted to determine whether or not the distal portion of the guidewire was inserted into the hub at least once within those five times.The evaluation criteria were as follows.

∘: means a case in which the distal portion of the guide wire could beinserted all five times

x: means a case in which the distal portion of the guide wire could notbe inserted at least once

The evaluation results are shown in Table 3 below.

TABLE 3 Catheter Inner Diameter of Catheter Main Body: φ1.05 mm GuideWire Inner Diameter of Hub Input Port: φ4 mm Inventive ◯ Example 1Comparative ◯ Example 1 Comparative ◯ Example 2 Comparative ◯ Example 3Comparative ◯ Example 4 Comparative X Example 5

As clear from Table 3, with respect to the guide wire according to theinventive example, the distal portion of the guide wire could beinserted into the hub all five times.

On the other hand, with respect to the guide wires obtained byrespective comparative examples, there occurred a case in which thedistal portion of the guide wire could not be inserted into the hub atleast once.

Also, the guide wires shown in FIG. 2 and FIG. 5 to FIG. 10 weremanufactured, and testing and evaluations similar to those of theaforesaid inventive example were executed with respect to them. Similarresults as those shown in Table 3 for the aforesaid inventive examplewere obtained also with respect to the guide wires shown in FIGS. 2 and5-10.

The guide wire disclosed here is a guide wire which includes a distalportion and a main body portion and which is provided with a first curveportion; a second curve portion on the distal side of the first curveportion and curved in a direction opposite the direction of curvature ofthe first curve portion, and a third curve portion on the distal side ofthe second curve portion and curved in a direction opposite thedirection of curvature of the second curve portion. A line contactingboth the first curve portion and the third curve portion forms an anglewith respect to an axial line of the main body portion. The guide wirepossesses quite good steerability characteristics when the guide wire isoperated.

The principles, embodiments and modes of operation of the guide wirehave been described in the foregoing specification, but the inventionwhich is intended to be protected is not to be construed as limited tothe particular embodiments disclosed. The embodiments described hereinare to be regarded as illustrative rather than restrictive. Variationsand changes may be made by others, and equivalents employed, withoutdeparting from the spirit of the present invention. Accordingly, it isexpressly intended that all such variations, changes and equivalentswhich fall within the spirit and scope of the present invention asdefined in the claims, be embraced thereby.

1. A guide wire comprising: an elongated member comprised of a straightmain body portion and a curved distal portion positioned on a distalside of the straight main body portion; the straight main body portionbeing straight and possessing an axis; the curved distal portion of theelongated member comprising a first curve portion, a second curveportion and a third curve portion, each of the first, second and thirdcurve portions having a shape that is curved in a state of the guidewire in which an external force is not applied to the guide wire; thefirst curve portion being more flexible than the main body portion; thefirst curve portion immediately following a distal end of the straightmain body portion and curving in a direction of curvature; the secondcurve portion being positioned distally of the first curve portion; thesecond curve portion curving in a direction of curvature that isopposite the direction of curvature of the first curve portion; thesecond curve portion being more flexible than the first curve portion,the second curve portion possessing a vertex; the third curve portionbeing positioned distally of the second curve portion, the third curveportion possessing a vertex; the third curve portion curving in adirection opposite the direction of curvature of the second curveportion; wherein a line contacting both the first curve portion and thethird curve portion forms an obtuse angle with respect to the axis ofthe main body portion; the line contacting both the first curve portionand the third curve portion is a first line, a second line parallel tothe first line contacts the second curve portion, and the elongatedmember possesses a distal most tip positioned between the first andsecond lines, wherein the first line, the second line, and the axis ofthe straight main body portion all extend along a common plane; and theentirety of the guide wire between the vertex of the second curveportion and the vertex of the third curve portion is positioned betweenthe first and second lines.
 2. The guide wire according to claim 1,wherein the first and third curve portions each comprise a vertex, andsaid line contacts the vertex of both the first curve portion and thethird curve portion.
 3. The guide wire according to claim 1, wherein theelongated member comprises a core wire and a resin coating portioncovering at least a distal portion of the core wire, the distal portionof the core wire covered by the coating portion comprising a flatportion.
 4. A guide wire comprising: an elongated member comprised of amain body portion and a distal portion positioned on a distal side ofthe main body portion; the elongated member comprising a core wire and aresin coating portion covering the core wire and contacting the corewire; the main body portion possessing an axis; the elongated membercomprising a first curve portion curving in a direction of curvature, asecond curve portion possessing a vertex and a third curve portionpossessing a vertex, each of the first, second and third curve portionshaving a shape that is curved in a state of the guide wire in which anexternal force is not applied to the guide wire; the second curveportion being positioned on a distal side of the first curve portion;the second curve portion curving in a direction of curvature that isopposite the direction of curvature of the first curve portion; thethird curve portion being positioned on a distal side of the secondcurve portion; the third curve portion curving in a direction oppositethe direction of curvature of the second curve portion; wherein a linecontacting both the first curve portion and the third curve portionforms an obtuse angle with respect to the axis of the main body portion;the line contacting both the first curve portion and the third curveportion is a first line, a second line parallel to the first linecontacts the second curve portion, and the elongated member possesses adistal most tip positioned between the first and second lines, whereinthe first line, the second line, and the axis of the main body portionall extend along a common plane; and the entirety of the guide wirebetween the vertex of the second curve portion and the vertex of thethird curve portion is positioned between the first and second lines. 5.The guide wire according to claim 4, wherein a portion of the elongatedmember shifting from the first curve portion to the second curve portionextends along a line forming a first angle with the axis of the mainbody portion, the elongated member possessing a distal most portionextending along a line forming a second angle with the axis of the mainbody portion, the first angle being greater than the second angle. 6.The guide wire according to claim 4, wherein the elongated membercomprises a portion shifting from the second curve portion to the thirdcurve portion that is parallel to the axis of the main body portion. 7.The guide wire according to claim 4, wherein the elongated membercomprises a portion shifting from the second curve portion to the thirdcurve portion that diverges relative to the axis of the main bodyportion in a direction towards a distal most end of the elongatedmember.
 8. The guide wire according to claim 4, wherein the elongatedmember comprises a portion shifting from the second curve portion to thethird curve portion, the portion converging relative to the axis of themain body portion in a direction towards a distal most end of theelongated member.
 9. The guide wire according to claim 4, wherein thefirst curve portion has a higher flexibility than the main body portionand the second curve portion has a higher flexibility than the firstcurve portion.
 10. The guide wire according to claim 4, wherein theelongated member comprises a core wire and a coating portion, thecoating portion being comprised of a resin covering at least a distalportion of the core wire.
 11. The guide wire according to claim 10,wherein the distal portion of the core wire covered by the coatingportion includes a flat portion.
 12. The guide wire according to claim10, wherein the core wire at the third curve portion is a flat portion,and the third curve portion possesses a higher flexibility than theflexibility of the second curve portion.
 13. A guide wire possessing anoutermost surface and comprising: an elongated member comprised of amain body portion having an axis, and a distal portion positioned on adistal side of the main body portion, the distal portion having a shapethat is curved in a state of the guide wire in which an external forceis not applied to the guide wire; the elongated member comprising a corewire and a resin coating portion covering the core wire and contactingthe core wire, and wherein the resin coating portion is the outermostsurface of the guide wire; a first curve portion provided at the distalportion of the elongated member, the first curve portion curving in adirection of curvature; a second curve portion positioned distally ofthe first curve portion and curving in a direction of curvature that isopposite the direction of curvature of the first curve portion, thesecond curve portion possessing a vertex; a third curve portionpositioned distally of the second curve portion and curved in adirection opposite the direction of curvature of the second curveportion, the third curve portion possessing a vertex; wherein the firstcurve portion possesses a higher flexibility than the main body portion,and the second curve portion possesses a higher flexibility than thefirst curve portion; and a first line contacts both the first curveportion and the third curve portion, and intersects the axis of the mainbody portion, a second line parallel to the first line contacts thesecond curve portion, and the elongated member possessing a distal mosttip positioned between the first and second lines, wherein the firstline, the second line, and the axis of the main body portion all extendalong a common plane; and the entirety of the guide wire between thevertex of the second curve portion and the vertex of the third curveportion is positioned between the first and second lines.
 14. The guidewire according to claim 13, wherein the third curve portion possesses aflexibility greater than or equal to the flexibility of the second curveportion.
 15. The guide wire according to claim 13, wherein the core wirepossesses a flat distal portion covered by the coating portion.
 16. Theguide wire according to claim 13, wherein the core wire at the thirdcurve portion is a flat portion, and the third curve portion possesses ahigher flexibility than the flexibility of the second curve portion. 17.A guide wire comprising: an elongated member comprised of a straightmain body portion and a curved distal portion positioned on a distalside of the straight main body portion; the straight main body portionbeing straight and possessing an axis; the curved distal portion of theelongated member comprising a first curve portion, a second curveportion and a third curve portion; each of the first, second and thirdcurve portions having a shape that is curved in a state of the guidewire in which an external force is not applied to the guide wire; thefirst curve portion immediately following a distal end of the straightmain body portion and curving in a direction of curvature; the secondcurve portion being positioned distally of the first curve portion; thesecond curve portion curving in a direction of curvature that isopposite the direction of curvature of the first curve portion; thesecond curve portion being more flexible than the first curve portion,the second curve portion possessing a vertex; the third curve portionbeing positioned distally of the second curve portion, the third curveportion possessing a vertex; the third curve portion curving in adirection opposite the direction of curvature of the second curveportion; wherein a line contacting both the first curve portion and thethird curve portion forms an obtuse angle with respect to the axis ofthe main body portion; the line contacting both the first curve portionand the third curve portion is a first line, a second line parallel tothe first line contacts the second curve portion; the entirety of theguide wire between the vertex of the second curve portion and the vertexof the third curve portion is positioned between the first and secondlines; the first curved portion comprising a flat portion having a widthand thickness, with the width of the flat portion being larger than thethickness of the flat portion, the first curved portion being moreflexible than the main body portion; and the curved distal portion ofthe elongated member being configured to turn around, to advance in amain body of a blood vessel and to not erroneously enter a branch of theblood vessel when a most distal tip of the guide wire extends into thebranch.
 18. The guide wire according to claim 17, wherein the elongatedmember comprises a core wire and a resin coating portion covering thecore wire and contacting the core wire, the core wire possessing a flatdistal portion covered and contacted by the coating portion.
 19. Theguide wire according to claim 17, wherein the elongated member comprisesa core wire and a resin coating portion covering the core wire andcontacting the core wire, the core wire at the third curve portion is aflat portion.
 20. The guide wire according to claim 19, wherein thethird curve portion possesses a higher flexibility than the flexibilityof the second curve portion.